I. Technical Field
The invention relates to a semitransparent mirror and optical units with such a mirror, and to methods for producing and operating such a mirror.
II. Discussion of Related Art
A transparent substrate is coated with thin layers for a semitransparent mirror. During the production, a predetermined ratio of reflectivity and transparency of the semitransparent mirror is set with the aid of the thickness of the layers. The disadvantage of such semitransparent mirrors is that this ratio of reflectivity and transparency can be changed only by depositing additional layers on the substrate, or by removing layer thicknesses by etching. Both of these require a high outlay on systems, material and method time. Corrections to the ratio of reflectivity and transparency of a semitransparent mirror also assume that the semitransparent mirror is removed from an optical unit and fed to the vapor deposition or etching installation, and is subsequently expensively reinstalled in the unit.